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Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021)最新文献

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Dual-frequency EVN Observations of a Large Sample of Distant Radio Quasars 远距离射电类星体大样本的双频EVN观测
Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021) Pub Date : 2022-03-08 DOI: 10.22323/1.399.0008
M. Krezinger, K. Perger, K. Gabányi, S. Frey, L. Gurvits, Z. Paragi, T. An, Yingkang Zhang, H. Cao, T. Sbarrato
{"title":"Dual-frequency EVN Observations of a Large Sample of Distant Radio Quasars","authors":"M. Krezinger, K. Perger, K. Gabányi, S. Frey, L. Gurvits, Z. Paragi, T. An, Yingkang Zhang, H. Cao, T. Sbarrato","doi":"10.22323/1.399.0008","DOIUrl":"https://doi.org/10.22323/1.399.0008","url":null,"abstract":"Máté Krezinger,a,b,∗ Krisztina Perger, Krisztina É. Gabányi, Sándor Frey, Leonid I. Gurvits, f Zsolt Paragi, Tao An, Yingkang Zhang, Hongmin Cao and Tullia Sbarrato Department of Astronomy, Institute of Geography and Earth Sciences, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary Konkoly Observatory, ELKH Research Centre for Astronomy and Earth Sciences, Konkoly Thege Miklós út 15-17, H-1121 Budapest, Hungary ELKH-ELTE Extragalactic Astrophysics Research Group, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary Institute of Physics, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary Joint Institute for VLBI ERIC, Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands f Department of Astrodynamics and Space Missions, Delft University of Technology, Kluyverweg 1, 2629 HS Delft, The Netherlands Shanghai Astronomical Observatory, Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, China School of Physics and Electrical Information, Shangqiu Normal University, 298 Wenhua Road, Shangqiu, Henan 476000, China INAF – Osservatorio Astronomico di Brera, via E. Bianchi 46, I-23807 Merate, Italy","PeriodicalId":136428,"journal":{"name":"Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133096888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Episodic ejection from a low-mass young stellar object traced by H2O masers 由H2O脉泽追踪的低质量年轻恒星物体的偶发抛射
Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021) Pub Date : 2022-03-08 DOI: 10.22323/1.399.0021
Zsolt Szab'o, O. Bayandina, 'A. K'osp'al, P. Ábrahám, K. Gabányi, Z. Nagy, V. L. Tóth, S. V. D. Heever
{"title":"Episodic ejection from a low-mass young stellar object traced by H2O masers","authors":"Zsolt Szab'o, O. Bayandina, 'A. K'osp'al, P. Ábrahám, K. Gabányi, Z. Nagy, V. L. Tóth, S. V. D. Heever","doi":"10.22323/1.399.0021","DOIUrl":"https://doi.org/10.22323/1.399.0021","url":null,"abstract":"We present the project of a VLBI study of the 22 GHz H 2 O maser in a prototypical low-mass protostellar system IRAS 16293-2422. The observation was conducted to characterise the cause of the newly discovered enhanced maser activity in the source and to study the source’s ejection behaviour as traced by maser emission. Single-dish monitoring and analysis of archival data indicate that the activity of the H 2 O maser in IRAS 16293-2422 has a cyclic character and traces episodic ejection events in the source. A new maser flare was recently discovered in a spectral feature that has never shown such a significant increase in flux density before. The flare of this feature seems to indicate the beginning of a new cycle of activity.","PeriodicalId":136428,"journal":{"name":"Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123575982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Comparison of Kerr and dilaton black hole shadows 克尔黑洞阴影与膨胀黑洞阴影的比较
Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021) Pub Date : 2022-03-08 DOI: 10.1051/0004-6361/202244866
Jan Roder, A. Cruz-Osorio, C. Fromm, Y. Mizuno, Z. Younsi, L. Rezzolla
{"title":"Comparison of Kerr and dilaton black hole shadows","authors":"Jan Roder, A. Cruz-Osorio, C. Fromm, Y. Mizuno, Z. Younsi, L. Rezzolla","doi":"10.1051/0004-6361/202244866","DOIUrl":"https://doi.org/10.1051/0004-6361/202244866","url":null,"abstract":"In the vicinity of black holes, the influence of strong gravity, plasma physics, and emission processes govern the behavior of the system. Since observations such as those carried out by the EHT are not yet able to unambiguously constrain models for astrophysical and gravitational properties, it is imperative to explore the accretion models, particle distribution function, and description of the spacetime geometry. Our current understanding of these properties is often based on the assumption that the spacetime is well-described by by the Kerr solution to general relativity, combined with basic emission and accretion models. We explore alternative models for each property performing general relativistic magnetohydrodynamic and radiative transfer simulations. By choosing a Kerr solution to general relativity and a dilaton solution to Einstein-Maxwell-dilaton-axion gravity as exemplary black hole background spacetimes, we aim to investigate the influence of accretion and emission models on the ability to distinguish black holes in two theories of gravity. We carry out three-dimensional general relativistic magnetohydrodynamics simulations of both black holes, matched at their innermost stable circular orbit, in two distinct accretion scenarios. Using general-relativistic radiative transfer calculations, we model the thermal synchrotron emission and in the next step apply a non-thermal electron distribution function, exploring representative parameters to compare with multiwavelength observations. We further consider Kerr and dilaton black holes matched at their unstable circular photon orbits, as well as their event horizons. From multiwavelength emission and spectral index analysis, we find that accretion model and spacetime have only a small impact on the spectra compared to the choice of emission model.","PeriodicalId":136428,"journal":{"name":"Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128317403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Simulated transverse distribution of polarization properties for parsec-scale jets in active galactic nuclei 活动星系核中秒差距尺度喷流偏振特性的横向模拟分布
Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021) Pub Date : 2022-02-24 DOI: 10.22323/1.399.0005
M. Butuzova, A. Pushkarev
{"title":"Simulated transverse distribution of polarization properties for parsec-scale jets in active galactic nuclei","authors":"M. Butuzova, A. Pushkarev","doi":"10.22323/1.399.0005","DOIUrl":"https://doi.org/10.22323/1.399.0005","url":null,"abstract":"We present numerical simulations of relativistic jet profiles in total and linear polarization intensity, degree of linear polarization, and direction of the jet’s electric vector position angles (EVPAs) transverse to the local jet axis. We consider the motion of jet segments along a helical path and, as a special case, motion in the radial direction. For these simulations we used various magnetic field configurations: (i) helical, with different twist angles, and (ii) toroidal in the central jet spine and poloidal at the jet sheath. The latter case was calculated for various values of the sheath thickness. We established the parameter sets that generally reproduce the transverse distributions of polarization properties observed with VLBI for the jets of the quasars 0836+710 (4C +71.07) and 1611+343.","PeriodicalId":136428,"journal":{"name":"Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021)","volume":"2047 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129812102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Single-baseline interferometer for mJy observations 用于mJy观测的单基线干涉仪
Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021) Pub Date : 2022-02-24 DOI: 10.22323/1.399.0033
J. Šteinbergs, A. Aberfelds, V. Bezrukovs, K. Šķirmante, A. Orbidans, I. Shmeld, R. Burns
{"title":"Single-baseline interferometer for mJy observations","authors":"J. Šteinbergs, A. Aberfelds, V. Bezrukovs, K. Šķirmante, A. Orbidans, I. Shmeld, R. Burns","doi":"10.22323/1.399.0033","DOIUrl":"https://doi.org/10.22323/1.399.0033","url":null,"abstract":"has developed an 800 m single-baseline interferometer consisting of 32 m (IR) and 16 m (IB) radio telescopes with 15 arcseconds of angular resolution. Irbene radio telescopes are operating at C/M/X-band (4.5-8.8 GHz). Raw telescope data are correlated with the Software FX Correlator (SFXC) [1] and output visibilities are calibrated with a ParselTongue ∗ pipeline. Data techniques provide a velocity resolution of 0.088 𝑘𝑚𝑠 − 1 and spectral resolution of 0.002 MHz and enabling observations to approach the theoretical sensitivity limit of the interferometer, at about 6 mJy for a 120 s integration. We propose to use the Irbene interferometer for discoveries in a new age of transient astrophysics. In this paper, we will show correlation and calibration schema and initial monitoring results.","PeriodicalId":136428,"journal":{"name":"Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021)","volume":"86 11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123178563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A study of the Milky Way scattering properties based on multi-frequency VLBA observations of the AGN core sizes 基于AGN核心尺寸的多频VLBA观测的银河系散射特性研究
Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021) Pub Date : 2022-02-24 DOI: 10.22323/1.399.0017
T. Koryukova, A. Pushkarev, A. Plavin, Y. Kovalev
{"title":"A study of the Milky Way scattering properties based on multi-frequency VLBA observations of the AGN core sizes","authors":"T. Koryukova, A. Pushkarev, A. Plavin, Y. Kovalev","doi":"10.22323/1.399.0017","DOIUrl":"https://doi.org/10.22323/1.399.0017","url":null,"abstract":"We present the results on the analysis of scattering properties of the Galaxy, based on multi-frequency (1.4 – 86 GHz) Very Long Baseline Interferometry (VLBI) data of active galactic nuclei (AGN) over the entire sky, with the exception of the region of far southern latitudes of the celestial sphere. The data of simultaneous observations at two frequencies, 2 and 8 GHz, and non-simultaneous multi-frequency observations of the apparent AGN VLBI jet origin (the core), allowed us to derive the characteristic value of the power-law index for the unscattered and scattered sources. We constructed the first detailed sky distribution map of the radio emission scattering power in the Galaxy and analyzed its properties. The scattered sizes of the cores are found to be significantly larger within the Galactic plane | 𝑏 | < 10 ◦ .","PeriodicalId":136428,"journal":{"name":"Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124412845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
PRECISE localizations of repeating Fast Radio Bursts 重复快速射电暴的精确定位
Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021) Pub Date : 2022-02-23 DOI: 10.22323/1.399.0035
B. Marcote, F. Kirsten, J. Hessels, K. Nimmo, Z. Paragi
{"title":"PRECISE localizations of repeating Fast Radio Bursts","authors":"B. Marcote, F. Kirsten, J. Hessels, K. Nimmo, Z. Paragi","doi":"10.22323/1.399.0035","DOIUrl":"https://doi.org/10.22323/1.399.0035","url":null,"abstract":"Fast Radio Bursts (FRBs) are extremely luminous and brief signals (with duration of milliseconds or even shorter) of extragalactic origin. Despite the fact that hundreds of FRBs have been discovered to date, their nature still remains unclear. Precise localizations of FRBs can unveil their host galaxies and local environments -- and thus shed light on the physical processes that led to the burst production. However, this has only been achieved for a few FRBs to date. The European VLBI Network (EVN) is currently the only instrument capable of localizing FRBs down to the milliarcsecond level. This level of precision was critical to associate the first localized FRB, 20121102A, to a star-forming region in a low-metallicity dwarf galaxy and physically related it to a compact persistent radio source. Analogously, a second repeating FRB, 20180916B, was found to just outside the edge of a prominent star-forming region of a nearby spiral galaxy. The PRECISE project (Pinpointing REpeating ChIme Sources with EVN dishes), starting from 2019, has observed hundreds of hours per year with a subset of EVN telescopes with the goal of localizing repeating FRBs discovered by the CHIME/FRB Collaboration. The ultimate goal of PRECISE is to disentangling the environments where FRBs can be produced. Here we present the state of the art of the FRB field, the PRECISE project, and the localizations achieved until now, which have unveiled a variety of environments where FRBs can be found that challenges the current models.","PeriodicalId":136428,"journal":{"name":"Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129658536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Three in One: The VLBI Radio View of the X-ray Quasar RX J1456.0+5048 三合一:x射线类星体RX J1456.0+5048的VLBI射电视图
Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021) Pub Date : 2022-02-19 DOI: 10.22323/1.399.0006
S. Frey, I. Tar, K. Perger
{"title":"Three in One: The VLBI Radio View of the X-ray Quasar RX J1456.0+5048","authors":"S. Frey, I. Tar, K. Perger","doi":"10.22323/1.399.0006","DOIUrl":"https://doi.org/10.22323/1.399.0006","url":null,"abstract":"RX J1456.0+5048 is a prominent X-ray source detected by ROSAT. There is ~100-mJy level radio emission associated with the X-ray source. However, interferometric observations with increasing angular resolution revealed that three distinct objects located within 2 arcmin are responsible for the measured total flux density. Whether these radio sources lining up in the sky are physically associated or just seen close to each other in projection is not immediately clear. In fact, incorrect cross-identification of the X-ray, optical and radio sources can already be found in the literature. Here we summarise the current knowledge about this intriguing group of objects, where two of the three sources show compact radio emission detected with very long baseline interferometry (VLBI). We present a VLBI image of one of them for the first time, based on archival European VLBI Network (EVN) data taken at 5 GHz.","PeriodicalId":136428,"journal":{"name":"Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127627409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Uncovering the radio emission of low-mass systems 揭示低质量系统的无线电发射
Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021) Pub Date : 2022-02-17 DOI: 10.22323/1.399.0016
Juan Bautista Climent Oliver, J. Guirado, M. A. Pérez Torres, M. Z. Zapatero Osorio, O. Zakhozhay
{"title":"Uncovering the radio emission of low-mass systems","authors":"Juan Bautista Climent Oliver, J. Guirado, M. A. Pérez Torres, M. Z. Zapatero Osorio, O. Zakhozhay","doi":"10.22323/1.399.0016","DOIUrl":"https://doi.org/10.22323/1.399.0016","url":null,"abstract":"Radio observations allow us to probe the nature of low mass objects, including ultracool dwarfs. Additionally, very long baseline interferometric observations provide the highest angular resolution in astronomy to date, which opens a window to measure dynamical masses of these objects in order to benchmark evolutionary models. We present here a multi-epoch, multi-frequency study of the substellar triple system VHS 1256 − 1257. We have found radio emission at 6 GHz and 33 GHz coincident with the expected position of the central binary of VHS 1256 − 1257. No emission is detected at higher frequencies (230 GHz and 345 GHz) nor at 5 GHz with VLBI arrays. The emission appears to be stable over almost 3 years at 6 GHz. These results can be well explained by non-thermal gyrosynchrotron emission originating at radiation belts present in both components and viewed equatorially. We also share preliminary results from our VLA observations of 5 low-mass binary systems and EVN observations of 4 ultracool dwarfs (including a binary).","PeriodicalId":136428,"journal":{"name":"Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127602569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Milliarcsecond analysis of the 6.7 GHz methanol maser outburst in HMYSO G24.33 HMYSO G24.33中6.7 GHz甲醇脉泽爆发的微弧秒分析
Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021) Pub Date : 2022-02-17 DOI: 10.22323/1.399.0020
A. Kobak
{"title":"Milliarcsecond analysis of the 6.7 GHz methanol maser outburst in HMYSO G24.33","authors":"A. Kobak","doi":"10.22323/1.399.0020","DOIUrl":"https://doi.org/10.22323/1.399.0020","url":null,"abstract":"","PeriodicalId":136428,"journal":{"name":"Proceedings of European VLBI Network Mini-Symposium and Users' Meeting 2021 — PoS(EVN2021)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125052922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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